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In this brief, we propose a novel wide-bandpass substrate integrated waveguide (SIW) filter in a compact circular cavity. It is implemented by etching spoof localized surface plasmon (SLSP) structure for more modes excitation. The dominant mode of SIW cavity and the seven modes of SLSP are employed to realize octuple-mode wideband filtering feature. Moreover, the two edges of the filter passband can be adjusted independently by changing the parameters of SIW or SLSP. Compared to traditional SIW wideband filters, the proposed structure dramatically increases the bandwidth meanwhile balances the size, complexity, and loss. A sample was fabricated and measured to validate the design. The measured results are in good agreement with the simulated ones, showing that a 3-dB relative bandwidth about 63% is achieved.

Background: L-Ascorbic acid (AA) is a kind of water soluble vitamin, which is mainly present in fruits, vegetables and biological fluids. As a low cost antioxidant and effective scavenger of free radicals, AA may help to prevent diseases such as cancer and Parkinson’s disease. Owing to its role in the biological metabolism, AA has also been utilized for the therapy of mental illness, common cold and for improving the immunity. Therefore, it is very necessary and urgent to develop a simple, rapid and selective strategy for the detection of AA in various samples. Methods: The molecularly imprinted poly(o-phenylenediamine) (PoPD) film was prepared for the analysis of L-ascorbic acid (AA) on gold nanoparticles (AuNPs) - multiwalled carbon nanotubes (MWCNTs) modified glass carbon electrode (GCE) by electropolymerization of o-phenylenediamine (oPD) and AA. Experimental parameters including pH value of running buffer and scan rates were optimized. Scanning electron microscope (SEM), fourier-transform infrared (FTIR) spectra, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were utilized for the characterization of the imprinted polymer film. Results: Under the selected experimental conditions, the DPV peak currents of AA exhibit two distinct linear responses ranging from 0.01 to 2 μmol L-1 and 2 to 100 μmol L-1 towards the concentrations of AA, and the detection limit was 2 nmol L-1 (S/N=3). Conclusion: The proposed electrochemical sensor possesses excellent selectivity for AA, along with good reproducibility and stability. The results obtained from the analysis of AA in real samples demonstrated the applicability of the proposed sensor to practical analysis.

Background: As a broad-spectrum antibiotic of the sulfonamide family, Sulfadimethoxine (SDM) has been widely utilized for therapeutic and growth-promoting purposes in animals. However, the use of SDM can cause residual problems. Even a low concentration of SDM in the aquatic system can exert toxic effects on target organisms and green algae. Therefore, the quantitation of SDM residues has become an important task. Methods: The present work describes the development of a sensitive and selective electrochemical sensor for sulfadimethoxine based on molecularly imprinted poly(o-aminophenol) film. The molecular imprinted polymer film was fabricated by electropolymerizing o-aminophenol in the presence of SDM after depositing carboxylfunctionalized multi-walled carbon nanotubes onto a glassy carbon electrode surface. SDM can be quickly removed by electrochemical methods. The imprinted polymer film was characterized by cyclic voltammetry, differential pulse voltammetry and scanning electron microscopy. Results: Under the selected optimal conditions, the molecularly imprinted sensor shows a linear range from 1.0 × 10-7 to 2.0 × 10-5 mol L-1 for SDM, with a detection limit of 4.0 × 10-8 mol L-1. The sensor was applied to the determination of SDM in aquaculture water samples successfully, with the recoveries ranging from 95% to 106%. Conclusion: The proposed sensor exhibited a high degree of selectivity for SDM in comparison to other structurally similar molecules, along with long-term stability, good reproducibility and excellent regeneration capacity. The sensor may offer a feasible strategy for the analysis of SDM in aquaculture water samples.

Tin (Sn)‐based perovskites with favorable optoelectronic properties and ideal bandgaps have emerged as promising alternatives to toxic lead (Pb)‐based perovskites for photovoltaic applications. However, it is challenging to obtain high‐quality Sn‐based perovskite films by solution process. Here, liquid‐exfoliated 2D transition‐metal dichalcogenides (i.e., MoS2, WS2, and WSe2) with smooth and defect‐free surfaces are applied as growth templates for spin‐coated FASnI3 perovskite films, leading to van der Waals epitaxial growth of perovskite grains with a growth orientation along (100). The authors find that WSe2 has better energy alignment with FASnI3 than MoS2 and WS2 and results in a cascade band structure in resultant perovskite solar cells (PSCs), which can facilitate hole extraction and suppress interfacial charge recombination in the devices. The WSe2‐modified PSCs show a power conversion efficiency up to 10.47%, which is among the highest efficiency of FASnI3‐based PSCs. The appealing solution phase epitaxial growth of FASnI3 perovskite on 2D WSe2 flakes is expected to find broad applications in optoelectronic devices., Liquid‐exfoliated 2D transition‐metal dichalcogenides (MoS2, WS2, and WSe2) are introduced as growth templates for spin‐coated FASnI3 perovskite films, leading to van der Waals epitaxial growth of perovskite grains with a growth orientation along (100). The good energy alignment in the NiOx/WSe2/FASnI3 structure facilitates hole extraction and suppresses interfacial charge recombination, leading to the best PCE of 10.47% for the PSC.

In this letter, a wide-angle narrowband leaky-wave antenna (LWA) based on substrate integrated waveguide-spoof surface plasmon polariton (SIW-SSPP) structure is proposed. Periodic slots are etched on both the top and bottom surfaces of SIW to introduce an SSPP mode. The periodic slots on the top surface are sinusoidally modulated to realize bidirectional LWA radiation. The problem of open stopband is solved by the asymmetrical design of the top and bottom slots. Thus, a wide bidirectional scanning range from −60° to +63° is achieved. Besides, the relative bandwidth of the fabricated antenna is reduced to only 9% by introducing the slow-wave effect of SSPP. It means the proposed antenna has a large scanning rate, or equivalently beam scanning range/bandwidth ratio.

As a promising lead-free perovskite candidate, tin-based halide perovskites such as FASnI3 have attracted extensive attention recently in photovoltaic applications. However, the relatively low efficiency and poor long-term stability of tin-based perovskite solar cells hinder their practical applications. Here, ammonium hypophosphite is introduced into the FASnI3 perovskite precursor to suppress the oxidation of Sn2+ and assist the growth of perovskite grains, leading to improved perovskite film quality and reduced defect density, and consequently, the device efficiency and open circuit voltage are substantially improved. More importantly, the solar cells exhibit pronounced enhancement of the long-term stability. This work provides a facile approach for improving the performance of tin-based perovskite solar cells by introducing ammonium hypophosphite as an antioxidant agent in the precursor solution.

Owing to their unique molecular geometry and packing modes in the solid state, curved organic semiconductor molecules such as hexabenzoperylenes and dibenzo[a,m]rubicene exhibit high hole mobilities of ∼1 cm2 V−1 s−1, which are much higher than the hole mobilities of the active layers in organic photovoltaics (OPVs). The efficiencies of OPVs based on a fullerene acceptor are relatively improved by over 20% by introducing high-mobility curved p-type organic semiconductors into the active layers as additives in only a few weight percentage. This can be attributed to the increased hole mobilities in the devices. In comparison, the significant efficiency enhancement cannot be observed when high-mobility planar molecules are introduced into the active layers. In view of the curved p-type semiconductors being more compatible with a fullerene acceptor in their molecular shape than a planar one, we consider that the intimate interaction between the curved molecule and the fullerene acceptor can enhance exciton dissociation and hole transfer and thus boost the power conversion efficiencies of the devices.

Tin-based perovskites with excellent optoelectronic properties and suitable band gaps are promising candidates for the preparation of efficient lead-free perovskite solar cells (PSCs). However, it is challenging to prepare highly stable and efficient tin-based PSCs because Sn2+ in perovskites can be easily oxidized to Sn4+ upon air exposure. Here we report the fabrication of air-stable FASnI3 solar cells by introducing hydroxybenzene sulfonic acid or its salt as an antioxidant additive into the perovskite precursor solution along with excess SnCl2 . The interaction between the sulfonate group and the Sn2+ ion enables the in situ encapsulation of the perovskite grains with a SnCl2 -additive complex layer, which results in greatly enhanced oxidation stability of the perovskite film. The corresponding PSCs are able to maintain 80 % of the efficiency over 500 h upon air exposure without encapsulation, which is over ten times longer than the best result reported previously. Our results suggest a possible strategy for the future design of efficient and stable tin-based PSCs.

Grain boundaries in organic–inorganic halide perovskite solar cells (PSCs) have been found to be detrimental to the photovoltaic performance of devices. Here, we develop a unique approach to overcome this problem by modifying the edges of perovskite grain boundaries with flakes of high-mobility two-dimensional (2D) materials via a convenient solution process. A synergistic effect between the 2D flakes and perovskite grain boundaries is observed for the first time, which can significantly enhance the performance of PSCs. We find that the 2D flakes can conduct holes from the grain boundaries to the hole transport layers in PSCs, thereby making hole channels in the grain boundaries of the devices. Hence, 2D flakes with high carrier mobilities and short distances to grain boundaries can induce a more pronounced performance enhancement of the devices. This work presents a cost-effective strategy for improving the performance of PSCs by using high-mobility 2D materials.

The COVID-19 pandemic is endangering the world due to the spread of respiration droplets with viruses. Medical workers and frontline staff need to wear respirators to protect themselves from breathing in the virus-containing respiration droplets. The most frequently used state-of-the-art respirators are of N95 standard; however, they lack self-decontamination capabilities. In addition, the viruses and bacteria can accumulate on the respirator surfaces, possessing high risks to the wearers over long-term usage. Photothermal decontamination is a contactless, fast, low-cost, and widely available method, capable of decontaminating the respirators. Herein, we report a plasmonic photothermal and superhydrophobic coating on N95 respirators, possessing significantly better protection than existing personal protection equipment. The plasmonic heating can raise the surface temperature to over 80 °C for this type of respirator within 1 min of sunlight illumination. The superhydrophobic features prohibit respiration droplets from accumulating on the respirator surfaces. The presence of the silver nanoparticles can provide additional protection via the silver ion's disinfection toward microbes. These synergistic features of the composite coatings provide the N95 respirator with better protection and can inspire experts from interdisciplinary fields to develop better personal protection equipment to fight the COVID-19 pandemic.

In recent years, digital coding and programmable metamaterials have brought new ideas to the fields of communication, detection, and imaging. Optimizing the reference signal matrix to achieve fast, accurate radar imaging has great practical significance for environment detecting. We selected the reference matrix based on the correlation of the matrix, and simulated the impact on the imaging results. The results of the experiment will inspire us to achieve accurate target imaging with less measurements and promote the development of fast and real-time imaging.

How to improve the accuracy of population spatialization by using downscaling technology has always been a difficult issue in academic research. The population spatialization model constructed from the global or local perspective alone has its own limitations that cannot capture the local and global characteristics of the population distribution. Based on the counties of Chongqing municipality in 2010, this paper uses the two steps of “removing-rough” rasterizationof partitioned multivariate statistical regression and the “getting-accuracy” of super-resolution convolutional neural network to construct a coupling model of population spatialization to complete global and local Feature learning and compare and analyze with other four schemes. The results show that the mean square error and root mean square error of the coupled model of partitioned multivariate statistical regression and super-resolution convolutional neural network are the lowest, especially in densely populated areas. Studies have shown that although super-resolution convolutional neural network has a good ability to downscale learning, it still does not reflect the heterogeneity of population spatial patterns well, and the coupling of multilevel global feature learning models and super-resolution convolutional neural network models can make up for this to a certain extent.

In this study, the translational trajectory of bubble in an ultrasonic standing wave at 22.4 kHz was observed using an imaging system with a high-speed video camera. This allowed the velocities of bubble be measured when the acoustic pressure at 20 kPa, 40 kPa and 60 kPa, which applied to indirectly measured the history force by using the acoustic and hydrodynamic forces balance model. It shown that bubbles driven at low acoustic pressure, the history force close to zero, and with the pressure increase the history force change to large, the ratio of F H / F QS from 0.33 at 40 kPa to 1.73 at 60 kPa, the result is different with prior research when the Reynolds numbers is large, and useful in the understanding of bubble moments in an acoustic field.

In this communication, we propose a high scanning rate leaky-wave antenna (LWA) based on a slow-wave substrate integrated waveguide (SIW) structure. The slow-wave effect is introduced by etching periodical slots on the top surface of SIW. The LWA radiation is subsequently realized by introducing sinusoidal modulation to the slots profile. Such a structure significantly improves the scanning rate of LWA due to the small group velocity at the slow-wave region. Simulation and measured results indicate that the proposed LWA scans a wide angle in a narrow bandwidth near the cutoff frequency of surface plasmon polariton. Within the frequency band 13.5–13.9 GHz (3% relative bandwidth), the measured scanning angle is from 2° to 37° with the measured gain all above 9.2 dBi.

In this paper, we propose a novel slow-wave half-mode substrate integrated waveguide (HMSIW) combined with spoof surface plasmon polariton (SPP) structure. In this design, subwavelength corrugated grooves are etched on the up metal layer of HMSIW to support an SPP mode. The dispersion and transmission characteristics of the proposed hybrid HMSIW-SPP structure are analyzed and compared with the classic HMSIW. To experimentally validate this design, a prototype is fabricated and measured. A slow-wave effect is clearly observed in the proposed hybrid transmission line, and its wavelength is reduced by over 50% without sacrificing its transmission performance. This structure features a simple architecture and excellent slow-wave effect.

In this paper, spoof surface plasmon polariton (SPP) is integrated in the closed substrate integrated waveguide (SIW) structure and a novel hybrid SIW-SPP guided-wave transmission line (TL) is proposed. In this design, the surface wave mode of SPP can be excited and transmitted inside the closed structure of SIW. The dispersion property of the proposed SIW-SPP hybrid structure indicates that it has both slow wave feature of SPP and fast-wave feature of SIW. With the low-pass feature of SSP and the high-pass feature of SIW, the proposed hybrid SIW-SPP TL becomes a bandpass filter (BPF) naturally. The concept of integrating SPP and SIW opens a new way to develop novel wideband BPFs. A broadband filter is fabricated to verify the theory and the measured passband is from 16.1 to 25.4 GHz with a relative bandwidth of 43.8%. The filter bandwidth can be easily controlled by tuning parameters, thus the proposed structure is attractive and useful for the design of various BPFs.

Low-voltage organic-field effect transi-stors (OFETs) using relaxor ferroelectric polymer poly (vinylidene fluoridetrifluoroethylene-chlorofloroethylene) P (VDF-TrFE-CFE)) were fabricated. The measured hysteresis loop and the threshold voltage shift under negative bias stress (NBS) are opposite to that of the reference device using low- ${k}$ CYTOP gate dielectric layer, in which the hysteresis and NBS-induced instabilities are explained by gate bias-induced charge trapping. The anomalous behaviors in the P (VDF-TrFE-CFE) OFETs are attributed to the stress-induced remnant polarization in P (VDF-TrFE-CFE), which induces additional mobile charges into the channel. By adding a thin CYTOP layer between the P (VDF-TrFE-CFE) layer and the semiconductor layer, the two effects of charge trapping and remnant polarization under gate bias are found to be neutralized with each other, resulting in low-voltage OFETs of negligible hysteresis and excellent NBS stability.

In this letter, a wide-angle beam-scanning antenna with circular polarization (CP) characteristic is proposed. The antenna consists of two layers. Microstrip spoof surface plasmon polariton (SPP) is introduced on the bottom layer as a slow-wave feeding line. A series of circular patches are placed on the top layer as radiating elements. Simulated and measured results indicate that beam-scanning angle of the proposed antenna is improved and CP beam-scanning ability is obtained by introducing perturbation on the radiating elements. In the operating band of 11–15 GHz, measured scanning angle of the fabricated antenna is from –32° to +34°. The antenna axial ratio (AR) is below 3 dB at the corresponding beam direction, and gain is above 12.8 dBi over the whole band. It has potential applications in radar and wireless communication systems for simple structure, low-cost fabrication, wide beam-steering, and CP properties.

Compressed sensing (CS) has been developed for several years in radar imaging applications, reducing the data needed for imaging. In addition, polarimetric radar system provides more information for imaging, and the imaging performance can be greatly improved via CS algorithms. In this paper, we overview three typical CS algorithms and carry out real experiments with missile warhead model data in full polarization ISAR imaging system to evaluate the performance of these algorithms. The conclusion drawn from the experiments can be used as a guide of choosing or designing CS algorithm for fully polarized ISAR CS imaging.

Phototransistors are recognized as highly sensitive photodetectors owing to their high gain induced by a photogating effect. However, the response speed of a typical phototransistor is rather slow due to the long lifetime of trapped carriers in the channel. Here, a novel Schottky barrier-controlled phototransistor that shows ultrahigh sensitivity as well as a fast response speed is reported. The device is based on a channel of few-layer black phosphorous modified with a MAPbI3-x Clx perovskite layer, whose channel current is limited by the Schottky barrier at the source electrode. The photoresponse speed of the device can be tuned by changing the drain voltage, which is attributed to a field-assisted detrapping process of electrons in the perovskite layer close to the Schottky barrier. Under optimal conditions, the device exhibits a high responsivity of 106 -108 A W-1 , an ultrahigh specific detectivity up to 9 × 1013 Jones, and a response time of ≈10 ms.

Flexible and light weight perovskite solar cells have attracted much attention recently for their broad potential applications especially in wearable electronics. However, highly flexible devices cannot be realized with the conventional transparent electrodes based on conductive oxides since they are rigid and brittle. Here, we demonstrate the fabrication of ultrathin and flexible perovskite solar cells with graphene transparent electrodes for the first time. The flexible devices with the structure of polyethylene terephthalate/graphene/poly(3-hexylthiophene)/CH 3 NH 3 PbI 3 /PC 71 BM/Ag are prepared on 20 µm-thick polyethylene terephthalate substrates by low-temperature solution process, which show the power conversion efficiency of 11.5% and high bending durability. Moreover, the devices demonstrate the power output per weight (specific weight) of about 5 W/g, which is much higher than those of conventional inorganic solar cells. This work paves a way for preparing flexible perovskite solar cells as well as other optoelectronic devices by using graphene transparent electrodes.

Fully converting the lead salt to perovskite is crucial for the performance of the perovskite solar cells via the sequential deposition method. By applying mixture of PbI2 and PbCl2 as the lead salts here, a fast conversion rate was found and a new PbICl phase was involved.

Although various metal nanoparticles have been used in organic photovoltaics (OPVs) for enhancing power conversion efficiencies (PCEs) based on surface plasmonic effects, no metal nanoparticles have been found to induce matchable broadband plasmonic enhancement in OPVs until now. Here, we report the introduction of Au@Ag core–shell nanocuboids (NCs) with broadband plasmonic enhancement in OPVs for the first time. The Au@Ag NCs show multimode localized surface plasmon resonance that can be tuned to match the light absorption spectra of OPVs by changing the Ag shell thickness. We find that both light scattering and near field enhancement induced by the NCs can substantially improve the device performance when the NCs are incorporated in the active layers. Under optimum conditions, the PCEs of the OPVs can be relatively improved by up to 22.8% by the NCs. The maximum average PCE of the OPVs we obtained is 10.42%, which is much higher than those of the previously reported plasmonic OPVs. This work demonstrates a convenient approach for improving the photovoltaic performance with broadband enhancement, which is applicable to not only OPVs but also many other types of solar cells.

Micro-motion dynamics produce Micro-range (m-R) signatures which are important features for target classification and recognition, provided that the range resolution of radar signal is high enough. However, dechirping the echo with reference measured by narrow bandwidth radar would generate the residual translational motion, which exhibits as random shifts of envelopes of range profiles. The residual translational motion would destroy the periodicity of m-R signatures and make a challenge to estimate rotational parameter. In this work, we proposed an efficient high-resolution range profile (HRRP)-based method to estimate rotational parameter, in which online measured reference distances are used to dechirp the radar raw echo. Firstly, the deduction for the modified first conditional comment of range profiles (MFCMRP) is introduced in detail, and the MFCMRP contain periodic and random components when dechirped by measured reference, corresponding to the rotational motion and the reference measured errors compared with actual reference. Secondly, the Wavelet Transform (WT) is utilized to separate the measured errors from the MFCMRP. The estimations of measured errors are used to compensate the MFCMRP, and then autocorrelation is performed on the estimated periodic component to obtain the estimation of rotational period. Lastly, the rotational amplitudes and phases are achieved by inverse Radon transform (IRT) of the compensated HRRP. The effectiveness of the proposed method in this paper is verified by synthetic data and measured radar data.

In spacecraft network, each nodes move in a predictable trajectory and the communication opportunities between them are often very short, therefore, network topology changes frequent and predictable. However, with the expansion of spacecraft network, how to maintain efficient and dynamic topology becomes increasingly crucial. In this paper, the topology design problem is studied in a spacecraft network where the dynamic topology and node efficiency can be predicted. First, a directed space-time graph that includes both spatial and temporal information is modeled for the spacecraft network. In order to reduce the impact of node congestion on the network performance, a new robust topology design problem which aims to balance the network load and minimize the total cost of the sparse structure while still maintaining the network connectivity over time is proposed. Second, two topology design algorithms which can significantly reduce the total cost of topology and maintain a space-time path connecting with robustness higher than the required threshold are proposed for this optimization problem. Finally, simulations results from random time-evolving and predicted spacecraft network demonstrate the efficiency of the proposed methods.

Although organic photovoltaic devices (OPVs) have been investigated for more than two decades, the power conversion efficiencies of OPVs are much lower than those of inorganic or perovskite solar cells. One effective approach to improve the efficiency of OPVs is to introduce additives to enhance light harvesting as well as charge transportation in the devices. Here, black phosphorus quantum dots (BPQDs) are introduced in OPVs as an additive. By adding 0.055 wt % BPQDs relative to the polymer donors in the OPVs, the device efficiencies can be dramatically improved for more than 10 %. The weight percentage is much lower than that of any other additive used in OPVs before, which is mainly due to the two-dimentional structure as well as the strong broadband light absorption and scattering of the BPQDs. This work paves a way for using two-dimentional quantum dots in OPVs as a cost-effective approach to enhance device efficiencies.

In order to address the frequent handover problem due to the satellite high-speed movement in LEO (Low Earth Orbit) satellite network, a MIPv6 (Mobile IPv6) satellite selection scheme based on distance detection is proposed to reduce the handover frequency significantly by selecting the access satellite with the maximum coverage time. Moreover, the handover latency and packet loss rate formula of MIPv6 with the different communication elevation angles and handover criterions are deduced in detail. Finally, simulations are carried out according to the settings of Iridium system. The simulation results show that the proposed satellite selection criterion can effectively reduce the handover latency and packet loss rate. This work also has some guiding significances for the setting of a communication elevation angle in satellite constellation design.

In the Space Information Network, the stratospheric broadband communication system has unique advantages due to the usage of high altitude platform (HAP) as its base station. Focusing on the optimization of HAP broadband communication networks, this paper proposed a multiobjective optimization deployment method that can match the users demand and guarantee the basic service of target area. The communication downlink performance for HAP single and multiple coverage are discussed, and presented the aggregate broadband efficiency model which equivalent to the upper limit of capacity. Combined with the users demand, we let capacity-demand matching degree (CDMD) and network coverage as two mutual restriction optimization objectives. Then applies the non-dominated sorting genetic algorithm 2 (NSGA-2) to solve constrained multi-objective optimization problem. Simulation results show that the method is effective, and obtained the solution's Pareto front which can be used as tradeoff choice for the final deployment plan.

Micro-Doppler, induced by micro-motion of targets, is an important characteristic of target recognition once extracted via parameter estimation methods. However, micro-Doppler is usually too significant to result in ambiguity in the terahertz band because of its relatively high carrier frequency. Thus, a micro-Doppler ambiguity resolution method for wideband terahertz radar using intra-pulse interference is proposed in this paper. The micro-Doppler can be reduced several dozen times its true value to avoid ambiguity through intra-pulse interference processing. The effectiveness of this method is proved by experiments based on a 0.22 THz wideband radar system, and its high estimation precision and excellent noise immunity are verified by Monte Carlo simulation.

Variable-capacity matching of continuously variable-capacity double-impeller torque converter applied to a loader was studied in the article. Static variable-capacity matching of continuously variable-capacity double-impeller torque converter was performed under the two-impeller state and slipping state. Dynamic variable-capacity matching based on the V-shaped operating cycle was simulated in order to reflect the matching performance of the double-impeller torque converter more intuitively. The working speed of double-impeller torque converter together with engine was analyzed when the loader shoveled different materials, and the power performance and fuel economy of the whole machine were calculated. The continuously variable-capacity double-impeller torque converter applied to a loader could not only meet the requirements of matching different loader working conditions but also enhances the power performance and fuel economy of the whole machine in running condition compared with the original torque converter.

Interprofessional education (IPE) is being increasingly recognised and prioritised in undergraduate medical education. While efforts are underway to integrate IPE into health professional curricula across Canada, the state of IPE in Canadian medical schools remains unclear. This study aims to assess the current practice of IPE in Canadian undergraduate medical curricula. An online survey was distributed to IPE directors (or designees) of all Canadian medical schools. The survey gathered details of the IPE experiences offered, curriculum structure, and perceived barriers to the programmes. The survey was completed by 12 of 17 Canadian medical schools and revealed that IPE is generally well represented in Canadian undergraduate medical education curricula. Reported barriers to IPE efforts included scheduling and funding limitations. By comparison, student interest was one of the least commonly cited issues. It would appear that students and faculty are interested in advancing the state of IPE in undergraduate medical education. The results of this study are crucial as IPE continues to evolve as a component of undergraduate medical curricula across the globe.

In this paper, we present a compact effective surface plasmon polariton (ESPP) frequency splitter induced by structural dispersion in substrate integrated waveguide (SIW). The frequency splitter consists of three SIW layers. Periodic wire arrays are placed on the interface of layers with relative effective permittivity in the opposite sign to support ESPP propagation, which can introduce transmission zero. By properly placing the substrates, the two passbands are spatially isolated from each other. The designed frequency splitter is numerically simulated and analysed. The numerical results demonstrate that the two passbands can be flexibly tuned by changing the relative permittivities of substrates and the lateral dimensions of SIW. The sample design achieves tunable dual passbands split and has a low profile and compact size.

The quality of perovskite films is critical to the performance of perovskite solar cells. However, it is challenging to control the crystallinity and orientation of solution-processed perovskite films. Here, solution-phase van der Waals epitaxy growth of MAPbI3 perovskite films on MoS2 flakes is reported. Under transmission electron microscopy, in-plane coupling between the perovskite and the MoS2 crystal lattices is observed, leading to perovskite films with larger grain size, lower trap density, and preferential growth orientation along (110) normal to the MoS2 surface. In perovskite solar cells, when perovskite active layers are grown on MoS2 flakes coated on hole-transport layers, the power conversion efficiency is substantially enhanced for 15%, relatively, due to the increased crystallinity of the perovskite layer and the improved hole extraction and transfer rate at the interface. This work paves a way for preparing high-performance perovskite solar cells and other optoelectronic devices by introducing 2D materials as interfacial layers.

Organolead halide perovskites have emerged as the most promising materials for various optoelectronic devices, especially solar cells, because of their excellent optoelectronic properties. Here, we present the first report of low-voltage high-gain phototransistors based on perovskite/organic-semiconductor vertical heterojunctions, which show ultrahigh responsivities of ~109A W–1 and specific detectivities of ~1014 Jones in a broadband region from the ultraviolet to the near infrared. The high sensitivity of the devices is attributed to a pronounced photogating effect that is mainly due to the long carrier lifetimes and strong light absorption in the perovskite material. In addition, flexible perovskite photodetectors have been successfully prepared via a solution process and show high sensitivity as well as excellent flexibility and bending durability. The high performance and facile solution-based fabrication of the perovskite/organic-semiconductor phototransistors indicate their promise for potential application for ultrasensitive broadband photodetection. High-gain phototransistors that operate from the ultraviolet to the near infrared could enable sensitive, broadband light detection. The excellent optoelectronic properties of organolead halide perovskites make them promising for various optoelectronic devices. Now, FY and co-workers from The Hong Kong Polytechnic University have fabricated low-voltage, high-gain phototransistors based on a vertical heterojunction consisting of a perovskite (CH3NH3PbI3-xClx) and an organic-semiconductor (PEDOT:PSS). Their high sensitivity is attributed mainly to the strong light absorption and long charge carrier lifetimes of the perovskite. The phototransistors can be fabricated on plastic substrates by solution processing, making them both flexible and compatible with cost-effective mass-production. Tests with light-emitting diodes that emit light at wavelengths of 370, 598 and 895 nanometers and a monochromator confirmed the broadband operation of the phototransistors.

Low Earth Orbit (LEO) satellite networks have been one trend for next-generation all-IP wireless networks with the development of satellite technology. Mobility management is one of the most challenging research topics for enabling mobility service in LEO satellite networks. Taking the highly topological dynamics characteristic of LEO satellite networks into consideration, we develop a mobility model, a dynamic network model and a packet transportation model to evaluate the handover performance of Mobile IPv6 (MIPv6) and Proxy Mobile IPv6 (PMIPv6). Based on these models, MIPv6 and PMIPv6 are then analyzed and compared in terms of handover latency, handover blocking probability and packet loss. The numerical results indicate that the performance of MIPv6 and PMIPv6 is affected by link condition, dynamic network topology and traffic in LEO satellite networks. In addition, PMIPv6, the network-based mobility management protocol, outperforms MIPv6 which is the host-based mobility management protocol.

For the regional coverage satellite constellation design optimization under the condition of multi-constrains, an optimization model with the orbital semi-major axis minimization and the percentage of coverage time maximization is built. Basic constellation models such as Walker and Flower are used to reduce the search space dimensions and NSGA-II is applied to solve the educed bi-objective optimization model. Moreover, 4+2N constellation model is proposed and compared with Walker and Flower models in terms of optimization performance by interconnecting Matlab and STK. Finally, some conclusions about how to choose the constellation models for regional constellation design are given.

Poor stability of organic–inorganic halide perovskite materials in humid condition has hindered the success of perovskite solar cells in real applications since controlled atmosphere is required for device fabrication and operation, and there is a lack of effective solutions to this problem until now. Here we report the use of lead (II) thiocyanate (Pb(SCN)2) precursor in preparing perovskite solar cells in ambient air. High-quality CH3NH3PbI3−x(SCN)x perovskite films can be readily prepared even when the relative humidity exceeds 70%. Under optimized processing conditions, we obtain devices with an average power conversion efficiency of 13.49% and the maximum efficiency over 15%. In comparison with typical CH3NH3PbI3-based devices, these solar cells without encapsulation show greatly improved stability in humid air, which is attributed to the incorporation of thiocyanate ions in the crystal lattice. The findings pave a way for realizing efficient and stable perovskite solar cells in ambient atmosphere., Poor stability of perovskite solar cells in humid conditions has hindered device fabrication and operation. Here, Tai et al. report the use of a lead thiocyanate precursor in preparing perovskite solar cells and without encapsulation showed better stability in air than typical perovskite solar cells.

In this paper, we present a novel dual-bandpass filter based on the substrate-integrated waveguide (SIW) and spoof surface plasmon-polariton (SSPP) hybrid structure. In this design, periodic subwavelength H-shaped units are etched on the top SIW surface to support SSPP mode. The dispersion and transmission characteristics of the proposed SIW–SSPP filter are analyzed. The dual-bandpass feature is observed for resonant tunneling of the H-shaped elements, and the passbands can be controlled easily by adjusting the filter parameters. Simulated and measured results demonstrate excellent transmission performance of the proposed filter.

Printing of metal bottom back electrodes of flexible organic solar cells (FOSCs) at low temperature is of great significance to realize the full-solution fabrication technology. However, this has been difficult to achieve because often the interfacial properties of those printed electrodes, including conductivity, roughness, work function, optical and mechanical flexibility, cannot meet the device requirement at the same time. In this work, we fabricate printed Ag and Cu bottom back cathodes by a low-temperature solution technique named polymer-assisted metal deposition (PAMD) on flexible PET substrates. Branched polyethylenimine (PEI) and ZnO thin films are used as the interface modification layers (IMLs) of these cathodes. Detailed experimental studies on the electrical, mechanical, and morphological properties, and simulation study on the optical properties of these IMLs are carried out to understand and optimize the interface of printed cathodes. We demonstrate that the highest power conversion efficiency over 3.0% can be achieved from a full-solution processed OFSC with the device structure being PAMD-Ag/PEI/P3HT:PC61BM/PH1000. This device also acquires remarkable stability upon repeating bending tests.

International audience; High-precision-positioning technology with nanometric resolution plays a vital role in driving segmented mirrors in very large astronomical telescopes (VLAT). Current positioning actuators in VLAT are generally based on hydraulic technology, flexible-hinge principle and motor-reducer approaches. Although these actuators have their own merits in their specific applications, they cannot satisfy the high-precise-positioning requirements in active and adaptive optics because of their inherent drawbacks such as hydraulic leakage, lagging, solid friction and insufficient accuracy. To improve the performance of actuators and meet the needs for positioning resolution and accuracy in active and adaptive optics in VLAT, this paper presents the design and implementation of a giant magnetostrictive assembled actuator (GMAA). The actuator features stable nano-resolution positioning, large stroke, instant response, and high load capacity. The design is based on a combination of dual level, i.e. coarse and fine drive regimes. A new large stroke, nanometric positioning GMAA is realized. In this paper the integrated design of the actuator, the control system and the test results from the prototype are presented. The test results prove not only the capacity and positioning accuracy of the actuator in large strokes, but also the effectiveness of the control system and the control method. The tests performed on a single GMA show that when its stroke is 0.6 mm, its positioning accuracy may reach to ±30 nm and the GMAA positioning accuracy may reach up to ±90 nm. The tests performed on the entire GMAA verify that it is able to perform a stroke of 2.2 mm with approximately 60 nm of displacement resolutions when 600 N of external load is applied.

A key unit operation in the production of phosphoric acid is the filtration needed to separate calcium sulphate dihydrate (CaSO₄·2H₂O, gypsum) crystals from an acid slurry. The filtration efficiency depends on the shape and size distribution (SSD) of the gypsum crystals produced from the upstream reactive crystallization. This article describes the construction of a first-principles model and computationally efficient numerical solver for the prediction of SSD during the reactive crystallization of gypsum while taking non-ideal phase equilibria and the effects of impurities (i.e., metal ions) into account. A population balance model couples the impurity compositions in the feed streams to the SSD for given process conditions, with the independent dimensions of the crystals being their length and width. Such a population balance model with two independent dimensions is able to represent rod-like crystals with varying aspect ratios (length/width). The compositions of all species in solution and the supersaturation driving force for crystal nucleation and growth are described using a mixed solvent electrolyte model that accounts for long-range, short-range, and ionic interactions. OLI software for computing the compositions is integrated with a Matlab implementation of the population balance model that is solved using the method of characteristics, which transforms the partial differential equations of the population balance model into a system of ordinary differential equations. This simulation method does not exhibit the numerical diffusion or dispersion common in other simulation methods, while being more computationally efficient. The crystal nucleation and growth rates are measured in a series of mixed-suspension mixed-product-removal experiments of various acid concentration, temperature, and impurity levels. A variety of models for the effects of impurities on the growth rates along the width and length dimensions are compared in terms of their ability to describe experimental observations. Keywords phosphoric acid particle shape crystallization population balance models gypsum